#include<iostream>
#include<vector>
#include<list>

class Single
{
private:
    Single()
    {
        std::cout << "single!\n"; 
    }
public:
    static Single *getInstance()
    {
        static Single eton;
        return &eton; 
    }

    void print()
    {
        std::cout << "xxx\n"; 
    }
};

int main() 
{
    Single::getInstance()->print();

    return 0; 
}
